What's called for specifically is an "11- by 18-inch (rimmed) baking pan (hs note: or jellyroll pan)" in this recipe. I made this once before and it was a hit, but I forgot about not having the correct pan, and I apparently guessed right last time.
Rather than fudge it (couldn't resist) again, should I just tally up the pans I have and approximate 198 inches?
None of the standard pan conversion charts that I could find had that size, but it looks like your recipe will work with an 11 cup volume pan. If this means your brownies are thicker or thinner than the original recipe, then adjust the cooking time accordingly. For thicker brownies you may also want to lower the temperature to keep the top from burning while you do the extra cooking.
As long as you have the same depth of pans as the one the recipe calls for, then it's not a problem to divide it all up between several pans that have the same area.
According to this chart, you should be able to use 1 - 9"x13" and 1 - 9"x9" pan. I have used this chart all the time... especially when I only want to make 1/2 or 1/3 recipe, I can quickly look and see what pan I should use.
http://blog.kitchennut.com/wp-content/uploads/2008/09/picture-5.png
